Noxious and Invasive Weeds

Invasive weeds are generally non-native plants introduced to North America from Europe and Asia. Weeds began entering this country in earnest in the mid-1800s. These plants have spread at an alarming rate because, unlike native species, there are no native insects, fungi, or diseases to control their growth and spread in this country. What initially began with a handful of plants in the 19th century now number in the hundreds of millions. These noxious weeds are destroying wildlife habitat and forage, threatening endangered species and native plants, increasing soil erosion and groundwater loss, and blocking recreational opportunities.

Estimates indicate that invasive plants are spreading at about 4,600 acres per day on federal lands alone in the Western United States. Weeds have invaded approximately 17 million acres of public rangelands in the West - more than quadrupling their range from 1985-1995. In northern California, yellow starthistle increased from 1 million acres in 1981 to 10 million acres today.

On the positive side, an inventory in 1996 showed that only about 8.5 million acres or 5% of BLM's 180 million acres had serious weed problems. Our challenge is to prevent the spread of these weeds before the situation gets more serious and requires a great deal of money and people to contain or control it.

Several BLM-California field offices maintain lists of noxious weeds that occur in their area. For more information, visit our field office websites below: